Which of the following statement is incorrect?

#include<iostream.h> 
int main()
{
    int arr[] = {1, 2 ,3, 4, 5}; 
    int &zarr = arr;
    for(int i = 0; i <= 4; i++)
    {
        arr[i] += arr[i];
    }
    for(i = 0; i <= 4; i++)
        cout<< zarr[i]; 
    return 0; 
}

#include<iostream.h> 
int main()
{
    int x = 80; 
    int y& = x;
    x++;
    cout << x << " " << --y;
    return 0;
}

#include<iostream.h> 
class CuriousTab
{
    int x, y; 
    public:
    void SetValue(int &xx, int &yy)
    {
        x =  xx ++;
        y =  yy; 
        Display();
    }
    void Display()
    {
        cout<< x << " " << y;
    }
};
int main()
{
    int x = 10;
    int &y = x;
    CuriousTab objCuriousTab;
    objCuriousTab.SetValue(x , y);
    return 0; 
}

#include<iostream.h>
class CuriousTabBase
{   
    public:
    CuriousTabBase()
    {
        cout<< "Base OK. "; 
    }
    ~CuriousTabBase()
    {
        cout<< "Base DEL. "; 
    }
};
class CuriousTabDerived: public CuriousTabBase
{
    public:
    CuriousTabDerived()
    { 
        cout<< "Derived OK. "; 
    }
    ~CuriousTabDerived()
    { 
        cout<< "Derived DEL. "; 
    }
};
int main()
{
    CuriousTabBase *basePtr = new CuriousTabDerived();
    delete basePtr;
    return 0;
}

#include<iostream.h>
class CuriousTabBase
{   
    public:
    CuriousTabBase()
    {
        cout<< "Base OK. "; 
    }
};
class CuriousTabDerived: public CuriousTabBase
{
    public:
    CuriousTabDerived()
    { 
        cout<< "Derived OK. "; 
    }
    ~CuriousTabDerived()
    { 
        cout<< "Derived DEL. "; 
    }
};
int main()
{
    CuriousTabBase    objB;
    CuriousTabDerived objD;
    objD.~CuriousTabDerived();
    return 0;
}